Republican Secretary of State Jon Husted acknowledged the sensitivity of immigration issues but said the information, which he requested, would be valuable in unique situations when a voter's citizenship is called into question. The database would not be used on a widespread basis to purge Ohio's voter rolls of non-citizens, he said.

"I feel like I have an obligation to pursue this to make sure we have all the tools necessary to make sure the integrity of the election system is upheld," Husted said.

Husted's request comes at a volatile time. The hotly contested presidential election has put a spotlight on voting rights issues across the country, and there already have been accusations in Ohio of voter suppression tactics by GOP lawmakers aimed at poor and minority voters. Just this week, President Barack Obama's re-election team sued Husted to allow in-person voting the three days before Election Day.

Voting rights advocates cautioned Husted to use the information carefully.

"There are likely to be many mistakes in any huge database and voters should not be denied the right to vote due to some bureaucrat's technical error," said Dan Tokaji, a professor at Ohio State University's Moritz College of Law and an expert on election law and voting rights issues.

The database, known as Systematic Alien Verification for Entitlement, or the SAVE program, contains about 100 million records that are available to benefit-granting agencies to determine an applicant's immigration status. The U.S. Department of Homeland Security oversees the program.

Husted asked for access to the records in late May after discussing the issue with other secretaries of state.

His request coincided with a legal battle over Florida's request for access. The U.S. Department of Justice fought to deny Florida access to the immigration database. But the Department of Homeland Security decided to grant Florida access after a federal judge ruled that Florida could remove non-citizens from its voter rolls.

Ohio is among about a dozen states that have requested the information.

But state Sen. Nina Turner, a Cleveland Democrat, questioned whether there is a problem with immigrants voting. She said it's unlikely non-residents would put themselves at risk by casting a ballot.

"It's just a red herring as far as I'm concerned," she said.

Husted said Ohio does not have a widespread problem of non-residents casting ballots. But such issues could arise in a presidential election year, when political parties and other groups are trying to get as many supporters to the polls as possible.

"From time to time, as we near the election and so forth, you'll get circumstances when a voter's eligibility is unknown or questioned," he said. "Up until this point, we'd have no way to accurately determine someone's citizenship."

Husted said the database would be used if a local elections board, a political party or an individual challenged a voter's citizenship. He said personal knowledge could be the basis for such a challenge.

A board of elections would report incidents to the secretary of state's office, which would then verify citizenship, Husted said.

State Rep. Kathleen Clyde, a Democrat from Kent who has been outspoken on voting rights, said the secretary of state should be more focused on making voting accessible to all Ohio citizens.

"Databases are flawed, and I am concerned that any wholesale effort to remove people from voting lists will prevent legitimate voters from exercising this most sacred right," she said in an e-mail.